Edging alpha texture viewport Blender
Well, finally, I I've found the way to "solve" it, if that could be called really an issue... It's true that Blender display badly meshes with alpha material if the map is low quality or small when I'm in the "Blender render" mode, well from what I've tested, that's what I've noticed...

However here, as I'm working with low poly assets and small maps, I just switched to "Blender Game engine" render, and by pressing "P" to have a preview of the "game", I don't have anymore those artefacts... There was as well the fact the shader was set in the shading tab to "shadeless" ! Unchecking this, is also important, even thought in this case I really want the shader to be shadeless...

Sorry for my ignorance... I guess you didn't think about that because that was too much simple...